Analysis of a novel functional polymorphism within the promoter region of the serotonin transporter gene (5-HTT) in Brazilian patients affected by bipolar disorder and schizophrenia

• Published in: American journal of medical genetics 1998-05, Vol.81 (3), p.225-227
• Main Authors: de Oliveira, João R. Mendes, Otto, Paulo A., Vallada, Homero, Lauriano, Valéria, Elkis, Helio, Lafer, Beny, Vasquez, Luciana, Gentil, Valentim, Passos-Bueno, M. Rita, Zatz, Mayana
• Format: Article
• Language: English
• Subjects: Adult and adolescent clinical studies; Biological and medical sciences; bipolar depression; Bipolar Disorder - ethnology; Bipolar Disorder - genetics; Brazil - ethnology; Carrier Proteins - genetics; Gene Frequency; Genes - genetics; genetics; Genotype; Humans; Medical sciences; Membrane Glycoproteins - genetics; Membrane Transport Proteins; Nerve Tissue Proteins; Polymorphism, Genetic; Promoter Regions, Genetic - genetics; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Psychoses; Schizophrenia; Schizophrenia - ethnology; Schizophrenia - genetics; Serotonin Plasma Membrane Transport Proteins; serotonin transporter; Tropical medicine
• ISSN: 0148-7299; 1096-8628
• DOI: 10.1002/(SICI)1096-8628(19980508)81:3<225::AID-AJMG4>3.0.CO;2-V

It has been suggested that the serotonin transporter (5‐hydroxytryptamine‐transporter or 5‐HTT) may be involved in the pathogenesis of affective disorders. Recently, Collier et al. (1996) found that the frequency of the low‐activity short variant (s) of the 5‐HTT‐linked poly*morphic region (5‐HTTLPR) was higher among patients with affective disorders than in normal controls. However, since the observed level of significance was not high, they suggest that these findings should be replicated in independent samples. We have analyzed 86 unrelated patients (47 with bipolar disorder and 39 with schizophrenia) and 98 normal controls from the Brazilian population for the 5‐HTTLPR. Statistical analysis revealed that the genotypes (LL, Ls, ss) as well as the estimated allele frequencies (L,s) did not differ significantly among the three studied groups or between bipolar and normal controls. In addition, although not statistically significant, the genotype ss in our sample was less frequent among our bipolar patients than in our normal controls (12.8% versus 16.3%) which is the opposite of what was found by Collier et al. (24% versus 18%) in the European study. Although it will be important to extend the present analysis in a larger sample, our preliminary results suggest that the 5‐HTTLPR does not seem to play a major role in the genetics of bipolar and schizophrenic disorders at least in this group of Brazilian psychiatric patients. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 81:225–227, 1998. © 1998 Wiley‐Liss, Inc.